Composites modulus

The moduli of metals, ceramics and glassy polymers below Tq reflect the stiffness of the bonds which link the atoms. Glasses and glassy polymers above are leathers, rubbers or viscous liquids, and have much lower moduli. Composites have moduli which are a weighted average of those of their components. 

Initial tensile Torsional moduli, Torsional moduli, Composition Tensile strength moduli methanol-dried air-dried... 

Thomason JL, Vlug MA. Influence of fiber length and concentration on the properties of glass fiber-reinforced polypropylene 1. Tensile and flexural modulus. Composites Part A Applied Science and Manufacturing. 1996 27(6) 477-84. 

Yeo, et al. [23,24] went on to make more complete studies of modulus-composition data using cross-poly(n-butyl acrylate)-Inter-cross-polystyrene, PnBA/PS, see Figure 6. Both the Davies and the Budlansky models fit reasonably well over wide ranges of composition, especially the Budlansky model. Other models, which in one form or another assume one continuous and one disperse phase, fit much less well. 

While significant evidence supporting the notion of dual phase continuity was obtained, particularly from modulus-composition studies, no direct observation had been successful with TEM due to its two-dimensional limitation. 

Figure 5. Modulus-composition curves for crass-polybutadiene-inier-cross-polystyrene semi-I and full IPNs (16). (a) Kerner equation (upper bound) (b) Budiansky model (c) Davies equation and (d) Kerner equation (lower bound). (Reproduced from ref. 23. Copyright 1981 American Chemical Society.)...

Figure 6. Modulus-composition behavior of cross-poly(n-butyl acrylate)-/ iter-cross-polystyrene IPNs and semi-I IPNs at 25 C. (Reproduced with permission from ref. 23. Copyright 1981 Polymer Engineering and Science.)...

Penetration temperature, expansion coefficient Elastic modulus, loss modulus Composition, weight loss as a function of temperature... 

PA-6 or PA-66 and >50% acrylic elastomers has been introduced by DuPont (Zytel FN) as a plasticizer-free, low modulus composition with good low-temperature toughness, resistance to thermal aging and solvents (particularly to fluorocarbon refrigerants) (Table 15.17). 

Radiation damage effects are likely to be of prime importance in organic matrix composites. Screening measurements to assess the severity of the problem are needed. For most of these materials, there is no low-temperature data base. Specifications for industrial laminates (NEMA/ASTM) are generally electrical in nature, and mechanical specifications may be necessary additions for low-temperature applications. Very few 4 K data exist for the advanced (high-modulus) composites and specialty fiberglass composites, which may be needed for low-temperature structural applications near pulsed coils. 

Thomason, J.L. Vlug, MA. (1996). Influence of Fibre Length and Concentration on the Properties of Glass Fibre-reinforced Polypropylene 1. Tensile and Flexural Modulus. Composites Part A Applied Science and Manufacturing, Vol.27, No.6, pp. 477-484 ISSN 1359-835X... 

Figure 12.2. Dependence of relative modulus (composite/polymer) on concentration for (A) the original Kerner equation (B) the modified Kerner equation (C) the Mooney equation. Circles correspond to experimental results. Solid curves are calculated with v = 0.35, Gf/Gp (relative modulus filler/polymer) = 25, and = 0.64.

The modulus-composition plots and their comparison with the models are shown in Figs. 5 and 6. Each model predicts the modulus fairly well within a narrow range of concentration. However, over the entire concentration range the experimental values fit the Budiansky model (21) best, which was expected, since the assumptions made in the model represent the phase inversion process. 

Both compatible and semi-compatible PPO blends that show blend densification exhibit a small synergistic maximum in their modulus-composition plots which can be modeled by the classical rule of mixtures for composites with an additional interaction term. The incompatible PPO blends exhibit no blend densification and can be modeled adequately by the series model for composites. 

The two types of support structures for the solar collectors and equipment that will be considered are the rigid deployable skeletal (RDS) structure and the rigidised inflatable flexible continuum (RIFC) structure both types of structure need to be lightweight and rigid and, in the case of the skeletal structure, high modulus composite materials would be used. In addition, the structures must be able to be folded to a minimum volume to be placed in the cargo bay of the Launch Vehicle, launched and deployed at LEO, and then taken to GEO by space tug,Wingo (2004). 

JL Thomason, MA Vlug. The influence of fibre length and concentration on the properties of glass fibre-reinforced polypropylene. Part 1. Tensile and flexural Modulus. Composites A 27 477-484, 1996. 

Similar structures for other aerospace venicles are in various stages of design, fabrication, and testing by United States firms. Lack of experience with large, high-modulus composite structures usually necessitates several iterations before development of the proper structure to meet specific flight requirements. For example. 

Thus, according to TGA and TMA data, it is possible to estimate the temperature interval, in which polyurethane isocyanurate polymers may operate without significant softening and degradation. For low-modulus polyurethane-isocyanurates, this range runs from -50 to 190°C, and for high-modulus composites it may reach 330°C. 

L. H. Sperling and D. W. Friedman, Synthesis and Mechanical Behavior of Interpenetrating Polymer Networks Poly(ethyl acrylate) and Polystyrene, J. Polym. Sci. A-2 7, 425 (1969). Synthesis of sequential IPNs. Modulus-temperature behavior. Modulus-composition behavior. 

The most common matrix materials of carbon-fiber composites are the polymers, also called resins or plastics. Carbon-reinforced polymers are low-density, high-strength, and high-modulus composites with extensive applications, especially in aerospace as mentioned above. Their cost is still high but is gradually decreasing as the fabrication techniques are becoming less labor-intensive. 

This is the basic rule of mixture and represents the highest Young s modulus composite, where all fibers are aligned in the direction of load. The minimum Young s modulus for a reasonable design (other than a preponderance of fibers being orientated transverse to the load direction) is the quasi-isotropic composite and can be approximated by... 

Composite curing stresses, called residual stresses are significant and, in the case of high-modulus composites, can cause part failure on cool-down from cure. These stresses wiU also cause Poisson s ratio strains. 

Compression ASTM D-695 (modified for high-modulus composites) Celanese, ASTM D-3410 IITRI, ASTM D-3410 sandwich beam, ASTM D3410... 

Compressive tests demonstrated anisotropy in mechanical behaviour, with an axial modulus up to 1.5 times greater than the transverse modulus. Composite scaffolds also showed viscoelastic behaviour with increased modulus for higher... 

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